Giovanni Boccaccio (1313-1375) begins his masterwork, The Decameron, with a vivid first-hand description of the bubonic plague’s arrival in Florence, Italy, in 1348. By the time it was all over, historians estimate that roughly one third of the population of Europe was dead. Boccaccio describes the disease itself—
. . . it began with swellings in the groin and armpit, in both men and women, some of which were as big as apples and some of which were shaped like eggs, some were small and others were large; the common people called these swellings gavoccioli. From these two parts of the body, the fatal gavaccioli would begin to spread and within a short while would appear over the entire body in various spots; the disease at this point began to take on the qualities of a deadly sickness, and the body would be covered with dark and livid spots, which would appear in great numbers on the arms, the thighs, and other parts of the body; some were large and widely spaced while some were small and bunched together. And just like the gavaciolli earlier, these were certain indications of coming death. . . .
. . . the rags of a poor man who had just died from the disease were thrown into the public street and were noticed by two pigs, who, following their custom, pressed their snouts into the rags, and afterwards picked them up with their teeth, and shook them against their cheeks: and within a short time, they both began to convulse, and they both, the two of them, fell dead on the ground next to the evil rags.
—and the human responses to incomprehensible suffering:
Because of all these things, and many others that were similar or even worse, diverse fears and imaginings were born in those left alive, and all of them took recourse to the most cruel precaution: to avoid and run away from the sick and their things; by doing this, each person believed they could preserve their health. Others were of the opinion that they should live moderately and guard against all excess; by this means they would avoid infection. Having withdrawn, living separate from everybody else, they settled down and locked themselves in, where no sick person or any other living person could come, they ate small amounts of food and drank the most delicate wines and avoided all luxury, refraining from speech with outsiders, refusing news of the dead or the sick or anything else, and diverting themselves with music or whatever else was pleasant. Others, who disagreed with this, affirmed that drinking beer, enjoying oneself, and going around singing and ruckus-raising and satisfying all one’s appetites whenever possible and laughing at the whole bloody thing was the best medicine; and these people put into practice what they heartily advised to others: day and night, going from tavern to tavern, drinking without moderation or measure, and many times going from house to house drinking up a storm and only listening to and talking about pleasing things. These parties were easy to find because everyone behaved as if they were going to die soon, so they cared nothing about themselves nor their belongings; as a result, most houses became common property, and any stranger passing by could enter and use the house as if he were its master. But for all their bestial living, these people always ran away from the sick. With so much affliction and misery, all reverence for the laws, both of God and of man, fell apart and dissolved, because the ministers and executors of the laws were either dead or ill like everyone else, or were left with so few officials that they were unable to do their duties; as a result, everyone was free to do whatever they pleased. Many other people steered a middle course between these two extremes, neither restricting their diet like the first group, nor indulging so liberally in drinking and other forms of dissolution like the second group, but simply not going beyond their needs or satisfying their appetite beyond the necessary, and, instead of locking themselves away, these people walked about freely, holding in their hands a posy of flowers, or fragrant herbs, or diverse exotic spices, which sometimes they pressed to their nostrils, believing it would comfort the brain with smells of that sort because the stink of corpses, sick bodies, and medicines polluted the air all about the city.
—Translated from the Italian by Richard Hooker (1993)
The entire text, in an older translation, can be found online here: https://sourcebooks.fordham.edu/source/boccacio2.asp. If your eyes are like mine, you will want to enlarge your screen’s display resolution to read it.